How do you calculate milligrams of caffeine in 60 mL sample?

Answer 1

You have to know the concentration first. That will either be in grams per milliliter (or milligrams per milliliter), or it could be in moles per liter (molarity). If it's given in grams per milliliter, just multiply that number by 60 and multiply by 1000.

If it's given in moles per liter, than first find how many moles in 60 mL by multiplying by 0.06, and then convert moles to grams using the molar mass of caffeine (194.19 grams per mole).

See the Related Questions for how to convert moles to grams.